Typologie de la peche et niveau de biomasse exploitee au Lac de Bolondo (region de la Bagoue ; nord de la Cote d’Ivoire)

Cette étude de caractérisation de la pêche au lac de Bolondo (environ 1,5 km²) dans la région de la Bagoué (Nord de la Côte d’Ivoire) a été réalisée pendant 12 mois (janvier à décembre 2014) à l’aide de questionnaire auprès des pêcheurs et de fiches d’enregistrement des captures. Elle montre que la pêche est majoritairement pratiquée par des non nationaux, essentiellement d’origine malienne (61,54 %). Les pêcheurs sont tous des illettrés. Ils sont en général des professionnels et 46,15 % parmi-eux s’adonnent exclusivement à l’activité de pêche. Aussi, la plupart des acteurs considèrent-ils la pêche comme une activité essentielle. Ils utilisent en majorité des nasses en filet de type papolo (58,82 %) et les filets maillants (25,49 %) comme principaux engins de pêche. Les pirogues en planches clouées constituent les seules embarcations utilisées. L’effort de pêche est élevé et oscille entre 4 et 8,67 pêcheurs/km². La production piscicole est estimée à 44,52 T et comprend des espèces économiquement importantes avec une proportion considérable de la biomasse du tilapia Oreochromis niloticus (33,73 %). Toutefois, l’utilisation d’engins non sélectifs, l’effort de pêche élevé, le manque de formation et l’insuffisance d’encadrement des acteurs restent des contraintes majeures au développement durable de cette activité.Mots-clés: Pêche, Production halieutique, Lac de Bolondo, Côte d’IvoireEnglish Title: Fishing typology and level of biomass exploited at Bolondo Lake Bagoué Region, northern Côte d'IvoireEnglish AbstractThis fishing characterization study at Lake Bolondo (approximately 1.5 km²) in the Bagoué region (northern Côte d’Ivoire) was carried out for 12 months (January to December 2014) using fishermen’s questionnaire and catchs registration form. It shows that fishing is mainly carried out by non-nationals, essentially of Malian origin (61.54%). The fishermen are all illiterate. They are generally professionals and 46.15% of them are engaged exclusively in the fishing activity. Also, most actors consider fishing as an essential activity. Most of them use trap nets (58.82%) and gillnets (25.49%) as main fishing gear. Canoes nailed planks are the only boats used. The fishing effort is high and oscillates between 4 and 8.67 fishermen / km². Fish production is estimated at 44.52 T and includes economically important species with a considerable proportion of tilapia biomass Oreochromis niloticus (33.73%). However, the use of non-selective gear, the high fishing effort, the lack of training and the insufficient supervision of the actors remain major constraints to the sustainable development of this activity.Keywords: Fishing, Fishery production, Bolondo Lake, Ivory Coas

Malaria transmission and insecticide resistance in Anopheles gambiae in Ellibou, Côte d'Ivoire

Background Malaria is a major public health problem in Côte d'Ivoire with a countrywide prevalence exceeding 60%. The main strategies to fight the disease include early diagnosis, prompt and effective treatment as well as individual and community effective preventive measures, such as the use of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). The deployment of any of these preventive measures must take into account the local conditions of malaria transmission, in particular the level of endemicity, the vectors involved in the transmission and the factors which influence the level of transmission. Unfortunately, resistance of malaria vectors to pyrethroids (PYRs), the main approved class of insecticides for treatment of bednets is widespread and constitutes a problem in disease control by the National Malaria Control Programme (NMCP). Ellibou is located in the southern part of Côte d'Ivoire and apart from the LLIN distribution campaign by the NMCP in 2014, no entomological study has been conducted in this locality. However, knowledge of the local malaria vectors and their resistance status to insecticides are essential to implement vector control strategies. Aim and objectives The aim of this PhD study was to determine key entomological parameters of malaria transmission and to assess the insecticide susceptibility of malaria vectors in Elibou, South Côte d'Ivoire. Specifically, we (i) determined the species composition of mosquitoes in Elibou, the sporozoite rate and the seasonal variation of malaria vector density over an entire year; (ii) assessed the insecticide susceptibility of the main malaria vector to the four conventional classes of insecticides used in public health and characterise the mechanisms involved in resistance to these insecticides; and (iii) investigated the knowledge, attitudes, practices and believes (KAPB) of the population in relation to the use of insecticides and insecticide resistance in malaria vectors. Methods We carried out an entomological survey, including larvae and adult mosquito collections in Elibou village over a 1-year period. To catch adult mosquitoes we performed pyrethroid spray catches (PSCs) and deployed CDC light traps (LTs). Adults mosquitoes were identified morphologically and diagnosted by PCR to genus and, where possible, to species level. The susceptibilty of female Anopheles moquitoes emerged from larvae to insecticides was assessed by World Health Organization (WHO) insecticide susceptibility assays, while we characterised the mechanisms involved in insecticide resistance by real-time reverse-transcription polymerase chain reaction (RT-PCR). Finally, a KAPB survey, using questionaires, focus group discussions (FGDs) and interviews, was carried out. Results We caught 2,383 adult mosquitoes, 884 specimens by CDC light traps and 1,499 by PSCs. We morphologically identified 10 different taxa, including three Anopheles taxa. Anopheles gambiae s.l. represented the predominant malaria vector. The other two Anopheles taxa were Anopheles funestus and Anopheles pharoensis representing less than 1% each. The molecular identification showed that An. gambiae s.s. (38.3%), Anopheles coluzzii (39.0%) and Anopheles arabiensis (19.5%) as the main malaria vectors in Elibou. To our knowledge, this is the first report of An. arababiensis in Côte d'Ivoire. We also found An. gambiae/coluzzii hybrids (4.7%). The other mosquito species included Aedes sp., Culex sp. and Mansonia sp. and represented 57.8% of the total of mosquitoes collected. The sporozoite rates were 5.3%. The numbers of adult An. gambiae s.l. mosquitoes increased considerably during the rainy seasons mainly between June and July. The main malaria vector was resistant to deltamethrin, dichloro-diphenyl-trichloroethane (DDT) and bendiocarb while susceptible to malathion. In the An. gambiae s.l. specimens we found the insecticide target site mutations kdr L1014F, L1014S and N1575Y, and the Ace-1 G119S at both the homozygous and heterozygous stage. While the L1014S was only found in An. arabiensis, nine individuals harboured simultaniousely the L1014F and L1014S alleles. The detoxification genes CYP6P3, CYP6M2, CYP6Z1, CYP6P4, CYP6P1, CYP9K1, CYP4G16 and GSTE2 were found to be overexpressed in all Anopheles tested from Ellibou. CYP6P4 and CYP6M2 were the most upregulated genes. The KAPB survey revealed that people have poor knowledge about insecticide resistance, while they felt that preventing measures were ineffective. The main reason given was that insecticides were diluted by the manufacturers as a marketing strategy to sell larger quantities of their products. More than a third of the farmers used agricultural pesticides for domestic purposes to kill weeds or mosquitoes. Conclusion The results of this study contribute to a better understanding of the main local malaria vectors and their resistance status to insecticides used in public health and agriculture as well as factors that lead to insecticide resistance and persistence of malaria affecting the NMCP activities in the fight against malaria. Here, we report for the first time the presence An. arabiensis among malaria vectors in Côte d’Ivoire. This finding is an early warning sign because An. arabiensis shows a different behaviour and ecology than An. coluzzii and An. gambiae s.s. Thus, different methods for vector control are required. Resistance to insecticides as observed in Ellibou is a great concern. Our results show that several resistance mechanisms are involved in insecticide resistance. In addition, the KAPB results show that the pesticides used for agriculture are also used in households for domestic purposes and might be a cause of insecticide resistance development in mosquitoes in Elibou. Given the misunderstanding of resistance by the local population, it is important to inform them about the current situation for awareness and sensitise them for a change in behaviour on the best use of insecticides and the environmental sanitation. For future studies, we recommend to investigate on the history of the onset of An. arabiensis in Côte d’Ivoire, its distribution, its resistance status and its implication in malaria transmission. For An. gambiae s.l., the use of an alternative insecticide such as pyrimiphos-methyl, an organophosphate for IRS, is recommended. However, An. arabiensis is primarily an outdoor biting mosquito, and hence IRS and LLINs may be less effective against this malaria vector. To this end, we recommend to implement an effective control using a transdisciplinary approach while involving the local population because it plays an important role in the spread of resistance. The conclusions of our study will guide decision makers to design and implement an effective vector control strategy in the Ellibou region and other localities with the same characteristics. Key words : Anopheles arabiensis, Anopheles gambiae, Ellibou, Côte d’Ivoire, insecticide resistance, metabolic resistance, transmission, malaria

Facteurs explicatifs de la Déscolarisation des enfants en Côte d’Ivoire : cas de Koffi-Amonkro

Cette étude vise à comprendre les facteurs explicatifs de la déscolarisation des enfants dans la localité de Koffi-Amonkro. L’enquête s’est appuyée sur les témoignages de 22 enfants déscolarisés dans une perspective phénoménologique. Les données ont été recueillies à l’aide d’un questionnaire. Elles ont été analysées à travers la « méthode d’analyse mixte ». Les résultats obtenus indiquent que la pauvreté des parents d’élèves, la négligence des parents d’élèves, les grossesses en milieu scolaire, le faible niveau d’expression en langue française des élèves, l’insuffisance de rendement scolaire et le faible niveau d’éducation des parents d’élèves sont des facteurs explicatifs de la déscolarisation de certains enfants à Koffi-Amonkro en Côte d’Ivoire.   This study aims to understand the explanatory factors behind the dropout of children in the locality of Koffi-Amonkro. The survey relied on the testimonies of 22 dropouts following a phenomenological approach. Data were collected using a questionnaire and analyzed through a mixed-method analysis. The results indicate that parental poverty, parental neglect, pregnancies within the school environment, the low level of proficiency in the French language among students, insufficient academic performance, and the low level of parental education are explanatory factors for the dropout of children in Koffi-Amonkro, Côte d'Ivoire

Spatial mapping and prediction of Plasmodium falciparum infection risk among school-aged children in Côte d'Ivoire

BACKGROUND: In Côte d'Ivoire, malaria remains a major public health issue, and thus a priority to be tackled. The aim of this study was to identify spatially explicit indicators of Plasmodium falciparum infection among school-aged children and to undertake a model-based spatial prediction of P. falciparum infection risk using environmental predictors. METHODS: A cross-sectional survey was conducted, including parasitological examinations and interviews with more than 5,000 children from 93 schools across Côte d'Ivoire. A finger-prick blood sample was obtained from each child to determine Plasmodium species-specific infection and parasitaemia using Giemsa-stained thick and thin blood films. Household socioeconomic status was assessed through asset ownership and household characteristics. Children were interviewed for preventive measures against malaria. Environmental data were gathered from satellite images and digitized maps. A Bayesian geostatistical stochastic search variable selection procedure was employed to identify factors related to P. falciparum infection risk. Bayesian geostatistical logistic regression models were used to map the spatial distribution of P. falciparum infection and to predict the infection prevalence at non-sampled locations via Bayesian kriging. RESULTS: Complete data sets were available from 5,322 children aged 5-16 years across Côte d'Ivoire. P. falciparum was the predominant species (94.5 %). The Bayesian geostatistical variable selection procedure identified land cover and socioeconomic status as important predictors for infection risk with P. falciparum. Model-based prediction identified high P. falciparum infection risk in the north, central-east, south-east, west and south-west of Côte d'Ivoire. Low-risk areas were found in the south-eastern area close to Abidjan and the south-central and west-central part of the country. CONCLUSIONS: The P. falciparum infection risk and related uncertainty estimates for school-aged children in Côte d'Ivoire represent the most up-to-date malaria risk maps. These tools can be used for spatial targeting of malaria control interventions

Facteurs explicatifs de la Déscolarisation des enfants en Côte d’Ivoire : cas de Koffi-Amonkro

Cette étude vise à comprendre les facteurs explicatifs de la déscolarisation des enfants dans la localité de Koffi-Amonkro. L’enquête s’est appuyée sur les témoignages de 22 enfants déscolarisés dans une perspective phénoménologique. Les données ont été recueillies à l’aide d’un questionnaire. Elles ont été analysées à travers la « méthode d’analyse mixte ». Les résultats obtenus indiquent que la pauvreté des parents d’élèves, la négligence des parents d’élèves, les grossesses en milieu scolaire, le faible niveau d’expression en langue française des élèves, l’insuffisance de rendement scolaire et le faible niveau d’éducation des parents d’élèves sont des facteurs explicatifs de la déscolarisation de certains enfants à Koffi-Amonkro en Côte d’Ivoire.   This study aims to understand the explanatory factors behind the dropout of children in the locality of Koffi-Amonkro. The survey relied on the testimonies of 22 dropouts following a phenomenological approach. Data were collected using a questionnaire and analyzed through a mixed-method analysis. The results indicate that parental poverty, parental neglect, pregnancies within the school environment, the low level of proficiency in the French language among students, insufficient academic performance, and the low level of parental education are explanatory factors for the dropout of children in Koffi-Amonkro, Côte d'Ivoire

Facteurs explicatifs de la Déscolarisation des enfants en Côte d’Ivoire : cas de Koffi-Amonkro

Cette étude vise à comprendre les facteurs explicatifs de la déscolarisation des enfants dans la localité rurale de Koffi-Amonkro, en Côte d’Ivoire, dans un contexte où le phénomène demeure préoccupant à l’échelle nationale. En effet, malgré les efforts gouvernementaux, le pays enregistre encore des taux élevés d’abandon scolaire, notamment en zones rurales. L’enquête s’est appuyée sur les témoignages de 22 enfants déscolarisés, dans une perspective phénoménologique. Les données ont été recueillies à l’aide d’un questionnaire à questions ouvertes et fermées, puis analysées à travers une méthode mixte (qualitative et quantitative). Les résultats obtenus révèlent que la pauvreté des parents, la négligence familiale, les grossesses précoces, le faible niveau d’expression en français, l’insuffisance de rendement scolaire, et le bas niveau d’éducation des parents sont les principaux facteurs identifiés. Ces résultats offrent des perspectives concrètes pour des politiques éducatives ciblées, en particulier en matière de sensibilisation parentale, d’inclusion linguistique, et de maintien des filles à l’école en milieu rural. This study aims to understand the explanatory factors behind school dropout among children in the rural locality of Koffi-Amonkro, Côte d’Ivoire, in a national context where dropout remains a persistent challenge. Despite government efforts, school abandonment rates remain high, especially in rural areas. The research is based on the testimonies of 22 school dropouts, using a phenomenological approach. Data were collected through a questionnaire combining open and closed-ended questions and analyzed using a mixed-method approach (qualitative and quantitative). The results highlight several key factors: parental poverty, family neglect, early pregnancies, low proficiency in the French language, poor academic performance, and low parental education levels. These findings offer practical insights for shaping targeted educational policies, particularly regarding parental awareness, linguistic inclusion, and the retention of girls in school in rural settings

情報通信技術、貧困、環境及び汚職に関する研究

広島大学(Hiroshima University)博士(学術)Doctor of Philosophydoctora

Effets de l’annonce du diagnostic de la COVID-19 sur les voyageurs en Côte d’Ivoire

The psychosocial effect of COVID-19 coupled with that of mobility restriction in air travelers is poorly documented. The objective of this study was to improve knowledge on the effect of COVID-19 on travelers in Côte d'Ivoire. The psychosocial effect of COVID-19 coupled with that of mobility restriction in air travelers is poorly documented. The objective of this study was to improve knowledge on the effect of COVID-19 on travelers in Côte d'Ivoire. A qualitative study was carried out with travelers consulting the COVID-19 team of the Institut Pasteur in Côte d'Ivoire. Data collection was carried out from August 13 to December 31, 2020 from travelers with a positive Covid-19 test through semi-structured individual interviews. Thirty-two travellers aged 18 to 69 were included. This analysis shows that the announcement of the diagnosis generates a wide range of negative psychological reactions due to the fact of being infected and the impossibility of travelling. Among these reactions are anxieties of dream annihilation, anger, aggressiveness, the feeling of injustice and revolt. These reactions include anxieties of dream annihilation, anger, aggressiveness, the feeling of injustice and revolt. In terms of financial impact, additional airfare and accommodation costs are the main additional costs mentioned. Furthermore, the impossibility of returning to work constituted a great financial loss, especially for those who left for a new job because the job was threatened. At the social level, several travelers mentioned the fear of being stigmatized. The announcement of a highly contagious infectious disease has a double challenge: the reduction of the psychosocial impact and the reduction of transmission.L’effet psychosocial de la COVID-19 couplé à celui de la restriction de mobilité chez les voyageurs aériens est très peu documenté. L’objectif de cette étude était d’améliorer les connaissances des effets de la COVID-19 sur les voyageurs en Côte d’Ivoire. Une étude qualitative a été réalisée auprès des voyageurs consultant l’équipe COVID-19 de l’Institut Pasteur de Côte d’Ivoire. La collecte des données a été réalisée du 13 août au 31 décembre 2020 auprès des voyageurs ayant un test de COVID-19 positif à travers des entretiens individuels semi-directifs. Trente-deux voyageurs âgés de 18 à 69 ont été inclus. Il ressort de cette analyse que l’annonce du diagnostic génère des réactions psychologiques négatives très variées dues au fait d’être infecté et à l’impossibilité de voyager. Au nombre de ces réactions, figurent des angoisses d’anéantissement de rêve, la colère, l’agressivité, le sentiment d’injustice et la révolte. Au niveau de l’impact financier, les frais supplémentaires sur le billet d’avion et les frais de séjour sont les principaux surcoûts mentionnés. En outre, l’impossibilité de reprendre le travail constituait une perte financière particulièrement pour ceux qui partaient pour un nouvel emploi. Au niveau social, la crainte d’être stigmatisé a été mentionnée par plusieurs voyageurs. L’annonce d’une maladie infectieuse très contagieuse a un double enjeu : la réduction de l’effet psychosocial et la diminution de la transmission